One carbon metabolism that includes vitamin B12 and homocysteine, plus vitamin D deficiency could all play a role in the onset of obsessive compulsive disorder (OCD), research suggests.

The new study, published in Psychiatry Research, ​investigated whether vitamin B12, homocysteine folic acid and vitamin D play a role in the cause (aetiology) of childhood OCD.

Led by Erman Esnafoğlu from Ordu University, Turkey, the team noted that one carbon metabolism – which includes vitamin B12 and homocysteine – has been investigated in many psychiatric disorders, while vitamin D has also been considered to contribute in a variety of psychiatric disorders in recent years.

“To the best of our knowledge the role of one carbon mechanism and vitamin D deficiency in children and adolescents with OCD has not yet been investigated,” wrote​ the Turkish team. “For this reason we aimed to investigate serum vitamin B12, folic acid homocysteine and vitamin D levels in children and adolescents in this study.”​

Esnafoğlu and colleagues reported that lower levels of vitamin B12 and higher levels of homocysteine in were found in OCD patients – suggesting that one carbon metabolism plays a role in the onset of the condition.

Furthermore, the team found that low vitamin D levels were linked to OCD, and that vitamin D status in patients had a negative correlation with disease severity.

“This study has demonstrated that there is a significant decrease in vitamin B12 and vitamin D and a significant increase in homocysteine in children and adolescents with OCD,”​ said the team – noting that vitamin D deficiency may be a risk factor for development of OCD.

They warned that further research is now needed in order to test the potential benefits of vitamin B12, folic acid and vitamin D supplementation.

Study details​

The team recruited 52 children and adolescent OCD patients plus 30 healthy controls into the study.

The OCD group were found to have higher points on anxiety and depression scales, said the team – who suggested that obsessions in OCD patients can “lead to nearly constant fear, repulsion, anxiety and the need for repetition.”​

“The findings of this study demonstrated that vitamin B12 and vitamin D levels were significantly lower in patients compared to healthy controls, whereas homocysteine was higher in the patient group,”​ noted Esnafoğlu and colleagues.